In a biometric authentication, a comparing is performed between a data for comparison obtained by a biometric sensor and a registered data that is registered in a database. As the number of registered user increases, both high accuracy of authentication and reduction of authentication time are demanded. A technology to improve authentication accuracy is disclosed (for example, with reference to Japanese Patent Application Publication No. 2008-65572 (hereinafter referred to as Document 1)). Reduction of authentication time is disclosed (for example, with reference to Japanese Patent Application Publication No. 2002-133416 (hereinafter referred to as Document 2)).